ion of the infected clothing house.

One thing more remained. There was one remote possibility that the men
who had remained free from the fever, in the noninfected room of the
mosquito house and in the infected clothing house, were in some
unsuspected way immune against the disease. To determine this, one of
each of the companies permitted himself to be bitten by an infected
mosquito, with the result that he promptly developed the disease. That
was the final, complete and crowning demonstration which made Camp
Lazear forever famous in the annals of humanity. At a single stroke the
pestilence which had been the haunting horror of the tropics was
potentially conquered. Dr. Reed proclaimed to the world that the
specific agent in the causation of yellow fever was a germ or toxin in
the blood of a patient during only the first three days of the attack,
which must be transmitted by the bite of a mosquito inflicted upon its
victim at least twelve days after taking it from the blood of the first
patient. In no other way was it possible to convey the infection. The
notion that it was conveyed through the air, in the breath of patients,
in their soiled clothing or the discharges of their bodies, was
baseless.

That historic achievement was alone sufficient to make that first year
of General Wood's administration in Cuba forever gratefully famous. Of
course the lesson thus learned was at once put into effect with all
possible thoroughness. War was declared upon the death-dealing mosquito.
In February, 1901, the campaign was begun by Major William C. Gorgas, U.
S. A., the chief sanitary officer of Havana. Every case of yellow fever
was immediately reported, and the patient was rigidly isolated during
the three days in which his blood was infective. All the rooms of his
house and the adjacent houses were closed to prevent the escape of
possible infected mosquitoes, and were then thoroughly fumigated so as
to destroy every insect within them. In this way the spread of the
disease was prevented. At the same time measures were taken to
exterminate the mosquitoes altogether, by depriving them of breeding
places. It was ascertained that the insect required for propagation a
certain amount of stagnant water, in which its eggs might be deposited
and hatched. Steps were therefore taken to drain or otherwise get rid of
all pools, or to apply to them a film of oil which would prevent the
insects from using them, and to screen carefully all